NASA wants a whole new crop of rocket engines from engine manufacturer Aerojet Rocketdyne. The space agency just awarded the company a $1.16 billion contract, restarting Aerojet's production line for its RS-25 engines. Four RS-25s will be used as the primary engines in NASA's next big rocket, the Space Launch System (SLS), which could take humans into deep space and on to Mars someday.
The RS-25 is no stranger to lifting heavy vehicles into space. These engines were also the main ones used on the Space Shuttle — the predecessor to SLS. However, modifications had to be made to the engines to ensure that they'll work on the SLS. The new rocket will experience colder temperatures than the Shuttle did, as well as greater pressures and speeds. NASA has been running a series of hot fire tests on the updated RS-25 engines this past year, to see if they hold up under the most extreme conditions.
The RS-25 is no stranger to lifting heavy vehicles into space
Those tests have proved successful, so now it seems NASA is ready to fully commit to the engines. Right now, NASA only has 16 leftover Shuttle engines that have been upgraded for SLS. The plan is to use those on the first four missions of the rocket, including the first two crucial test flights known as Exploration Mission-1 and Exploration Mission-2.
But moving forward, NASA is going to need a lot more engines than that. Unlike the Space Shuttle, the SLS won't be recovered after each launch, so an entirely new rocket must be built for each flight. That means NASA is going to need a steady stream of engines for the foreseeable future. This new contract will help cover that, as it gives Aerojet the money it needs to pay for the equipment and materials needed to make the engines, as well as funds for employees working on the production line. The funding runs from November 2015 through September 30th, 2024. NASA hasn't made any bulk orders for the engines yet, but this new contract includes one order of a certified RS-25 engine from the company.
Aerojet is also making the engines more affordable and more expendable for SLS. The RS-25 will be built with fewer parts and welds, and it's also built with new manufacturing techniques that include 3D printing and digital X-rays.
The SLS is NASA's replacement for the Space Shuttle, which will go deeper into space than any crewed vehicle has gone before. The rocket will carry people in the Orion crew capsule to lunar orbit in 2020, and after that, the plan is for SLS to carry people to the surface of Mars sometime in the 2030s. However, the first version of the SLS has yet to be built; its first test flight is scheduled for September 2018.